What’s the cost difference between having a system with batteries and a system without batteries? Is being off the grid worth it?

Sincerely,

Sam in Los Angeles

Dear Sam,

Great question. Short answer is that battery tied systems are NOT worth the extra cost for many reasons. Let me count the ways.

Most if not all State cash rebates require your solar panels to be connected to the utility. So you if you’ve got power going to your house already and you want free money from your State, then I would stay on the grid. (Go to the DSIRE site for summaries of state incentives.)

Grid tied only systems are relatively easy to install, requiring less time and money for installation costs.

Similarly, without batteries, you have to buy fewer pieces of electrical and safety components.

Grid tied systems are very low maintenance. Battery systems, even those that are just backup systems, are less efficient, require more space and maintenance, not to mention frequent battery replacement costs.

For the 25 to 30 years of your solar panel life, the grid will almost always back you up at night and on cloudy days. It is extremely rare in America when the electricity goes down. Power is generally restored within hours or within a few days at the very worst.

If you consider that you’re not eligible for state rebates, you could be losing $20,000 or more between the rebate cash that a State like California would have given you, plus the extra equipment and labor costs.

To be balanced, battery tied people have some non-financial advantages:

You can have it both ways. That is, you can be on the grid and have a battery backup system in case of a black out. (Consider how often this happens, however. In most of grid-tied of America, a black out may happen once a year or less. Is that worth 20 grand? If you’re in a rural community with no utility wires for miles, then it could be worth it.)

Grid tied systems with a battery backup are still eligible for most State cash rebates and the 30% Federal Tax Credit. (However, neither of these discounts will apply to any batteries or battery components.)

Grid tied systems with a battery backup need fewer batteries, less maintenance, and less space than a system that has batteries only. (But you still have higher install labor costs, extra equipment, and you’ll eventually have to replace the batteries.)

With a battery system that is not tied to the grid, you can proudly say that you are completely independent of coal burning utility companies, that you use 100% renewable energy from the sun, and that your lights and refrigerator will be on after an earthquake or problem with the grid. (However, as noted earlier, you are also responsible for a separate, well ventilated space to house the batteries, maintenance of the batteries, and the inevitable replacement costs every 5-10 years–depending on how well you maintain your batteries.)

So it’s up to you, but if you really want the most affordable system that is 95-99% reliable and less expensive, I would go with a solar system that is only tied to the grid without backup.

The battery thing has never made all that much sense from an emissions perspective since you’re not going to get back the same amount of power that it took to charge them, while with a grid-tied system you will be offsetting your neighbors’ emissions. What matters is not any individual carbon footprint, but how it all collectively adds up.

Generators fail during outages and it can then take weeks to get them repaired, trust me, I lost mine on day 1 of a 7-day outage which happens frequently in new England. One storm I had to drive 20 miles to find a gas station that had power. Once I went solar with battery backup, I have never been interrupted or without power. Plus, I don’t have to worry about thieves stealing my generator at night or while I’m at work. or spending $3.50 a gallon to run a 100w light bulb and TV during outages. Batteries are awesome, only use the power you need, when you need it, no waste.

I want to build a solar system that is off grid. I don’t trust the current electrical system, sooner or later it will go down, don’t want to be tied to it.
But I don’t want batteries, can’t afford them, not good at taking care of things. I have a whole house generater that will be connected up to a 500 gallon propane tank. Will this be sufficinet to keep the house powered at night when the sun is down? I live in Arizona, sun most days.

We get this a ton. Answer is always the same. Batteries rarely make sense unless you are way far out there and dropping a new power-line is cost prohibitive. Otherwise, they’re too expensive.

A generator is the real solution for when your power goes out. Get solar to save money, and get a generator for when the power goes out, but they are effectively separate things. Think of the grid as your battery backup. It works most of the time, almost 100% of the time.

Switch to solar and save $36.45/mo on average ($0 installations may be available)

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